A8N-SLi Premium memory divider issues

[Kalessian]

Does anyone know how the memory dividers actually work on the Premium?

Forever, I've been running like this:

300x9=2700 with 1x1GB memory at 2.5-3-3-5 1T@247mhz. The divider I was using was 333mhz, which is 5/6, right? Well 5/6 of 300 is 250mhz, not 247. In fact, ALL of the dividers EXCEPT 1/2 run a few mhz lower than I would expect.

Anyhow, this is my problem. I added another 1GB stick, the same kind as before (Patriot LL). This stick can only go up to 2.5-3-3-5 1T@240mhz 2.9v by itself (meaning I can no longer use the 333mhz divider and keep my overclock), which is fine with me.

Put both sticks in, dual channel can only go to 2.5-3-3-5 1T@235mhz 2.85v. I'm TOTALLY OK with that, since that's like 6 GB/s bandwith in Sandra. However, this is with the 400mhz divider, which is 1:1, so I'm only running my CPU at 235x9=~2.1ghz.

So next, I bump up the CPU speed back to my normal 2.7ghz, right? At 300FSB, if I run the 266mhz multiplier (2/3), the memory will only be running 200mhz (- a few mhz for that strange reason). So say the memory would run 197mhz. That's below stock.

Guess what? Computer won't boot because of the memory. I've tried everything, switching slots, running single channel, dual channel, raising the FSB while lowering the multi so I can use the 1/2 divider.

If I use a divider, my memory WILL NOT go over 175mhz (DDR350) in ANY configuration. Most of the time it won't go over 165mhz, but I found a "hole" where I'm running it 173mhz now, at the cost of running my cpu 2.4ghz.

I'm stumped. My memory can run in the board dual channel up to 235mhz in 1:1. Any other divider screws it up. So it has to be the dividers that are the problem.

Should I switch to 1009? I've tried 1005 bios and beta 1011.

 

[wanderer27]

Set me straight, are you using 2x1GB in slots 1 & 3 ?

You remembered to change your HTT multiplier so you're not running your Hypertransport > 1000 ? With 300 FSB you should be using the 3x multiplier for a Hypertransport of 900 (4 -> 1200)

At 300 FSB with the 333 Divider your Memory would be running at about 250. That may be stretching things a bit with 2GB. Might want to loosen your timing some or go to 2T with that much Memory at those speeds, as it may be a strain for the Memory Controller /NF4.

The 266 Divider should put you at about 199.5 (DDR399).

 

[Kalessian]

Thanks for your reply.

Read my post carefully, though, and you'll notice I WAS running the 266 divider on 300mhz:

So next, I bump up the CPU speed back to my normal 2.7ghz, right? At 300FSB, if I run the 266mhz multiplier (2/3), the memory will only be running 200mhz (- a few mhz for that strange reason). So say the memory would run 197mhz. That's below stock.

Guess what? Computer won't boot because of the memory. I've tried everything, switching slots, running single channel, dual channel, raising the FSB while lowering the multi so I can use the 1/2 divider.

To answer your question, I ran HTT multi at 3x, so yes, 300x3=900.

I've tried EVERY possible configuration. Slots 1 & 2 SingleCh, 1 & 3 DualCh, 2 & 4 SC, 2 & 4 DC.

I've tried loosening the timings, I've tried 2T, I've tried everything I can think of to get that memory to work at 200mhz while my CPU is overclocked, but I can't.

Do you think that the increased FSB + that much ram could strain the NF4? Should I overvolt the chipset, then?

 

[Kalessian]

These settings work:


311 FSB, 2.8ghz CPU, 933 HTT, slots 1 & 3 DC, 200mhz divider, 2-3-2-5 1T @ 155mhz(DDR310). I CAN'T bring it up to 266mhz divider, which would be ideal for me.

267 FSB, 2.4ghz CPU, 1068 HTT, slots 1 & 3 DC, 266mhz divider, 2-3-2-5 1T @ 173mhz (DDR346). This is the highest I can do with the 266mhz divider.

330 FSB, 2.64ghz CPU, 990 HTT, slots 2 & 4 DC, 200mhz divider, 2-3-2-5 2T @ 165mhz (DDR330). This is the highest I can do with the 200mhz divider. Notice 2T.

235 FSB, 2.1ghz CPU, 940 HTT, slots 1 & 3 DC, 400mhz divider, 2.5-3-3-5 1T @ 235mhz (DDR470). This is the highest I can do with the 400mhz divider. I'm RAM limited at this point.


I can't get the 333mhz divider to work at all, and single channel is actuall LESS stable than dual channel. I want to be able to run my CPU 2.7-2.8ghz while running my ram 200mhz+

Right now, that seems impossible. How much can I get for this ram on FS/FT? Maybe I'll pick up the TwinLL Corsair stuff.

 

[wanderer27]

Well, the issues I've seen (not just this MB) really seem to start showing up around the 2 GB mark, and it doesn't affect everyone so it's really hard to nail down. The worst config seems to be 4x512MB.

Another factor that plays into this is your CPU version. If you're running an older (> 3-4 months ?), then the odds greatly increase for having troubles with large amounts of RAM. I'm taking a guess here, but with the OC you're getting on your 3000, I'd suspect you may have an older CPU - the newer ones don't seem to OC as well from what I've seen.

The odd thing here is you can't get the 333 Divider to work. Usually when someone has a problem it's that they can't the 400 to work and it keeps defaulting to the 333.

What BIOS are you using ? I'm running 1007 and haven't had any problems, but I don't have 2 GB and I'm not OC'ing. I don't know what the newer ones are supposed to fix, but it may be worth a shot trying an older BIOS.

Only other thought is that maybe either a CPU or RAM BIOS setting is still in an "Enabled" mode for Auto - OC'ing. That could definitely give you some headaches.

You said you can't get the 333 to work - period ? Even at Stock speeds ? If this is truely the case then you may have a bad NF4 or corrupted BIOS possibly. If you can't get it to work with clean BIOS update (older or newer version), you may be looking at a RMA.

 

[Kalessian]

Thanks.

I'm using the 1011-001 beta BIOS, and I'm thinking about switching to 1009.

None of the auto settings are on, in fact none of the bios settings are off. I've done everything right.

I'm sure the 333mhz divider will work if I run EVERYthing stock. But what's the point?

I'm literally stuck. Now I have to either run my memory at 150mhz (DDR300) or buy new sticks. I guess I won't be getting that 7900GT after all.

So what do you think? Is it the motherboard/NF4 that's having trouble with this particular memory, or is it my CPU, which means no 2GB configuration will work?

 

[wanderer27]

The reason I asked if the 333 worked at Stock is that if it didn't, I'd say you definitely have a MB/NF4 problem.

It might be worthwhile to see how high you can get it to work with the 333 Divider. On one MB (don't remember which) there was "hole" - it work to a certain speed and then if wouldn't for the next 40 - 50 MHz, and then it would start working again. I'm thinking it was around 240 that it'd fail, and 275 or so it'd start working again. Something to check out.

The only other thing that comes to mind right now is maybe trying 3-3-3-8 timings. Yeah, they're slower timings, but if you get a good FSB it'll more than make up for it.

 

[Kalessian]

You're right. I found a weird hole, just like you said. I can run stable at 2.6ghz using 3-3-3-8 1T(!) timings on the 333mhz divider. I swear it wasn't able to do this, previously.

Maybe I changed something I forgot about. Anyhow, I'm semi-happy with this setup for now. Maybe I can do some more testing later.

Thanks for the advice - it helped out a lot.

 

[wanderer27]

:thumbsup:

Glad I could help.